Communication terminal and information processing system

ABSTRACT

An information processing system includes a reader/writer, a communication terminal, and a wireless IC tag. The communication terminal includes an electric field antenna including a coupling portion that defines a magnetic field antenna, and the antenna portion is housed in a pen-shaped casing. The antenna portion is coupled to an electric field antenna of the reader/writer through an electric field, and the coupling portion is coupled to the wireless IC tag through a magnetic field. The reader/writer communicates with the wireless IC tag as a result of the coupling portion being brought close to the wireless IC tag.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to communication terminals, andspecifically to communication terminals which can be used in radiofrequency identification (RFID) systems, and information processingsystems including the communication terminals.

2. Description of the Related Art

To date, as article management systems, RFID systems have been developedthat perform non-contact communication between reader/writers thatgenerate electromagnetic induction fields and wireless tags that areattached to articles and contain predetermined information, therebytransmitting information. As an example of such RFID systems, JapaneseUnexamined Patent Application Publication No. 2003-99184 discloses aninformation processing system in which, by integrating an RFID device(wireless IC tag) into an input pen, an information processing apparatus(reader/writer) reads information from the RFID device and recognizesthe user of the pen or characters written by the pen when the RFIDdevice is within a communication range of the information processingapparatus.

However, in the information processing system described above, becauseoperation requires that the RFID device (wireless IC tag) be within acommunication range of the reader/writer and because a communicationrange in the HF band or UHF band is short, there is a problem in thatcommunication is possible only over a very short distance.

Japanese Unexamined Patent Application Publication No. 2001-240217discloses an inventory management system, for inventory management in abook store, including a plurality of handy terminals that communicatewith a master station. However, the handy terminal, which includes abattery and a signal processing circuit, has a complex configuration anda large size.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention provide a communicationterminal and an information processing system that realize a longcommunication range between a reader/writer and a wireless IC tag usinga simple configuration.

A communication terminal according to a first preferred embodiment ofthe present invention includes an antenna portion including a couplingportion, wherein the antenna portion and the coupling portion handle asignal used in a single information processing system, and a signalreceived by the antenna portion is transmitted from the coupling portionand a signal received by the coupling portion is transmitted from theantenna portion.

An information processing system according to a second preferredembodiment of the present invention includes a reader/writer; acommunication terminal; and a wireless IC tag, wherein the communicationterminal includes an antenna portion including a coupling portion, theantenna portion communicates with the reader/writer, the couplingportion communicates with the wireless IC tag, and information stored inthe wireless IC tag is read by the reader/writer.

The communication terminal includes an antenna portion including acoupling portion, the antenna portion communicates with thereader/writer, and the coupling portion communicates with the wirelessIC tag. In other words, the communication terminal mediatescommunication between the reader/writer and the wireless IC tag and,hence, communication is possible even when the reader/writer and thewireless IC tag are spaced apart from each other by a distance that doesnot allow communication to be performed by them alone. In addition, thecommunication terminal does not need a battery or an informationprocessing circuit and, hence, has a simple configuration.

According to various preferred embodiments of the present invention,since a communication terminal mediates communication between a wirelessIC tag and a reader/writer, a communication range is increased.

The above and other elements, features, steps, characteristics andadvantages of the present invention will become more apparent from thefollowing detailed description of the preferred embodiments withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an information processing systemaccording to a first preferred embodiment of the present invention.

FIG. 2 is perspective view of a layered structure of a coil antenna of awireless IC tag.

FIG. 3 is a perspective view of a first modification example of acoupling portion of a communication terminal.

FIG. 4 is a perspective view of a second modification example of acoupling portion of a communication terminal.

FIG. 5 is a perspective view of a third modification example of acoupling portion of a communication terminal.

FIG. 6 is a perspective view of a first modification example of awireless IC tag.

FIG. 7 is a perspective view of the wireless IC tag and boost antennaillustrated in FIG. 6.

FIGS. 8A and 8B are equivalent circuits of second and third modificationexamples of a wireless IC tag.

FIG. 9 is a perspective view of a fourth modification example of awireless IC tag.

FIG. 10 is a perspective view of a fifth modification example of awireless IC tag.

FIG. 11 is a perspective view of a sixth modification example of awireless IC tag.

FIGS. 12A and 12B both are perspective views of an informationprocessing system according to a second preferred embodiment of thepresent invention.

FIG. 13 is a perspective view of a first modification example of acommunication terminal.

FIG. 14 is a perspective view of a second modification example of acommunication terminal.

FIG. 15A is a perspective view of a third modification example of acommunication terminal, and FIG. 15B is an enlarged perspective view ofan antenna portion.

FIG. 16 is a perspective view of a fourth modification example of acommunication terminal.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, preferred embodiments of a communication terminal and aninformation processing system according to the present invention aredescribed with reference to the attached drawings. Note that componentsand portions common in the figures are denoted by the same referencesymbols and duplicate descriptions thereof are omitted.

First Preferred Embodiment

Referring to FIG. 1, an information processing system 100A according toa first preferred embodiment includes a reader/writer 50, a plurality ofcommunication terminals 60A, and wireless IC tags 1A. The reader/writer50 includes a main body 51 that includes an information processingcircuit and the like and an electric field antenna 53 connected to themain body 51 by a signal line 52.

The communication terminal 60A functions as a pen reader/writer andincludes an antenna portion 61 having a coupling portion 62. The antennaportion 61 is housed in a tube-shaped casing 64 and the coupling portion62 is arranged in the tip portion of the casing 64. The antenna portion61 preferably is an electric field dipole antenna including twoelectrodes 61 a and 61 b and is coupled to the electric field antenna 53of the reader/writer 50 through an electric field. The coupling portionis a magnetic field loop antenna having a loop-shaped electrode arrangedbetween the electrodes 61 a and 61 b and is coupled to coil antennas 20Aand 20B of the wireless IC tag 1A through a magnetic field, as will bedescribed below in detail. The coupling portion 62 preferably isloop-shaped with an area that is about the same as the total area of theantennas 20A and 20B of the wireless IC tag 1A. The antenna portion 61including the coupling portion 62 is preferably formed on a surface of aresin film using a thick film or thin film conductor, for example, andthe coupling portion 62 is bent by about 90 degrees.

The wireless IC tag 1A includes a wireless IC chip 10 to processtransmission and reception signals having predetermined frequencies andthe two coil antennas 20A and 20B. The wireless IC chip 10 preferablyincludes a clock circuit, a logic circuit, a memory circuit, and thelike, for example. The wireless IC chip 10 has necessary informationstored therein and includes a pair of input/output terminal electrodes,which are not illustrated, arranged on the back surface thereof.

The coil antennas 20A and 20B preferably include conductors wound incoils. First ends of the coil antennas 20A and 20B are connected to theinput/output terminal electrodes of the wireless IC chip 10 and thesecond ends are electrically connected to each other. The antennas 20Aand 20B are arranged such that the winding axes thereof are arranged atdifferent positions in plan view, and the winding directions thereof arethe same. As will be described with reference to FIG. 2, the antennas20A and 20B are formed preferably by stacking a plurality of coilconductors formed in a substrate 21. The wireless IC chip 10 is mountedon the substrate 21.

In the information processing system 100A, high-frequency waves (in theHF band, UHF band, or higher-frequency band) transmitted from theelectric field antenna 53 of the reader/writer 50 are received by theantenna portion 61 of the communication terminal 60A and transmitted tothe coupling portion 62. By bringing the coupling portion 62 arranged atthe tip portion of the casing 64 close to the wireless IC tag 1A,magnetic flux based on a signal with a predetermined frequency radiatedfrom the coupling portion 62 passes through the coil antennas 20A and20B, whereby a current flows through the antennas 20A and 20B. In otherwords, the coupling portion 62 is electromagnetically coupled to theantennas 20A and 20B. This current is supplied to the wireless IC chip10, thereby operating the wireless IC chip 10.

On the other hand, a response signal from the wireless IC chip 10 isradiated from the coil antennas 20A and 20B to the coupling portion 62.The signal is supplied to the antenna portion 61, received by theantenna 53 of the reader/writer 50, and read by the main body 51.

In other words, in the first preferred embodiment, the antenna portion61 and the coupling portion 62 handle signals used in the singleinformation processing system 100A, for example, in the UHF band or inan RFID system, where the antenna portion 61 resonates at a frequencynear the operation frequency of the reader/writer 50, and thecommunication terminal 60A mediates communication between thereader/writer 50 and the wireless IC tag 1A. Hence, communicationbecomes possible even when the reader/writer 50 and the wireless IC tag1A are spaced apart from each other by a distance that does not allowcommunication to be performed by them alone. Specifically, since theelectric field antenna 53 of the reader/writer 50 and the antennaportion 61 of the wireless IC tag 1A are coupled to each other throughan electric field, communication is realized over a relatively longrange. Further, an existing electric field antenna can be used as theelectric field antenna 53 of the reader/writer 50. In addition, sincethe antennas 20A and 20B of the wireless IC tag 1A are coupled to thecoupling portion 62 through a magnetic field and since a magnetic fieldhas more attenuation than an electric field, short-range communicationis performed. Hence, a specific wireless IC tag 1A can be reliably readeven when a plurality of the wireless IC tags 1A are provided. Further,since the communication terminal 60A and the reader/writer 50 arewirelessly coupled to each other, a plurality of the wireless IC tags 1Acan be simultaneously read using a plurality of the communicationterminals 60A.

Since the communication terminal 60A, which includes the antenna portion61 having the coupling portion 62, does not require a driving powersupply such as a battery and a peripheral circuit thereof or a wirelesscommunication device such as a Bluetooth (trademark) device, thecommunication terminal 60A can be a small and low-cost terminal.Further, since the coupling portion 62 is arranged in the tip portion ofthe casing 64, the antenna portion 61 can be easily coupled to thecoupling portion 62.

The communication terminal 60A preferably is a pen terminal, and byholding the casing 64 by hand and bringing the communication terminal60A close to the wireless IC tag 1A, which is an object to be read,communication with the wireless IC chip 10 is performed. A human bodymay also function as an antenna that is coupled to an electric field.Hence, when the antenna portion 61 is arranged in a portion that is heldby hand, a human body also operates as an antenna, whereby thesensitivity of the antenna portion 61 is increased.

The pen-type casing 64 of the communication terminal 60A may beconfigured to function as an object having a practical function ratherthan only as a communication terminal of an RFID system. For example,the communication terminal 60A may be a ball point pen or cellularphone.

With regard to the wireless IC tag 1A, since the coil antennas 20A and20B have the same winding direction, currents generated in the antennas20A and 20B do not cancel out each other, resulting in increased energytransmission efficiency. In other words, the communication range betweenthe coupling portion 62 and the antennas 20A and 20B is increased.Further, by forming the antennas 20A and 20B so as to have layeredstructures and forming the coil conductors of each antenna at locationsthat are superposed in plan view, the opening areas of the coils can beincreased, whereby magnetic flux passing therethrough is increased.Hence, the communication range is increased.

It is preferable that an imaginary portion of the impedance of thewireless IC chip 10 be a conjugate of the imaginary portion of theimpedance of the coil antennas 20A and 20B at a frequency used incommunication. In other words, the resonant frequency of the coilantennas 20A and 20B is preferably near the frequency used. It is morepreferable that the real portions of the impedances be the same.

Specifically, when the coil antennas 20A and 20B include layeredstructures with large openings, a large inductance as well as a smallsize is realized, resulting in a reduction in the size of the wirelessIC tag 1A. By using waves with short wavelengths near 950 MHz, forexample, a further reduction in size is realized. For example, in thecase in which a frequency in the UHF band is used in communication, thewireless IC tag 1A having a length of about 3.2 mm, a width of about 1.6mm, and a height of about 0.5 mm is realized, for example.

Here, exemplary layered structures of the coil antennas 20A and 20B aredescribed with reference to FIG. 2. The substrate 21 is a stackcontaining a plurality of sheets on which electrodes, conductors, andvia holes are formed. On the first layer, electrodes 31 a and 31 bconnected to the input/output terminal electrodes of the wireless ICchip 10 are provided. The second to fourth layers have coil conductors32 a, 32 b, 33 a, 33 b, 34 a, and 34 b provided thereon, and the fifthlayer has a connection coil conductor 35 provided thereon. The coilconductors 32 a, 32 b-34 a, and 34 b are connected through via holeconductors 36 a and 36 b so as to define coils, whereby the antennas 20Aand 20B are provided. First ends of the antennas 20A and 20B areconnected to the two ends of the coil conductor 35 through via holeconductors 37 a and 37 b. The second ends of the antennas 20A and 20Bare connected to the electrodes 31 a and 31 b through via holeconductors 38 a and 38 b.

Although the sheets of the substrate 21 may be formed of a resin havinga normal dielectric constant of 3 to 4, they are preferably formed of amaterial with a higher dielectric constant, for example, a ceramic witha dielectric constant of 7 or more.

By providing the antennas 20A and 20B with a layered configuration, notonly is the opening widened but also operational stability is realized.In other words, since capacitance between the coil conductors isdetermined by a material (sheet material) between the coil conductors,the effect of the dielectric constant of an object to which the wirelessIC tag 1A is attached is small (variations in stray capacitance areunlikely to be generated), whereby variations in the inductance of thecoils are small. Hence, variations in resonant frequency are small and astable communication range is realized. Particularly, by using amaterial with a high dielectric constant for the substrate 21, theimpedance within the substrate 21 is almost completely determined, andis unlikely to be affected by the usage environment.

The coupling portion of the antenna portion can be modified into variousshapes, and first to third modification examples of a preferredembodiment of the present invention will be described below. First,referring to FIG. 3, the coupling portion may be planar electric fieldantennas 62A and 62B, rather than loop-shaped antennas as describedabove. Since the coil antennas 20A and 20B of the wireless IC tag 1Apreferably are two separate components, each of the antennas 20A and 20Bgenerate a potential difference and an electric field. Hence, the planarelectric field antennas 62A and 62B can also be made to operate. Notethat when the electric field antennas 62A and 62B are used as thecoupling portion, the antenna of a wireless IC tag may be of theelectric field type.

Referring to FIG. 4, the coupling portion may be a loop-shaped magneticfield antenna 62C including a plurality of turns. Since the magneticfield strength is increased, the communication range can be increased.

Referring to FIG. 5, the coupling portion may include a first coilantenna 62D and a second coil antenna 62E similar to the coil antennas20A and 20B. First ends of the coil antennas 62D and 62E areelectrically connected to the antenna portion 61 and the second endsthereof are electrically connected to each other. The coil antennas 62Dand 62E are arranged such that the winding axes thereof are arranged atdifferent positions in plan view, and the winding directions thereof arethe same.

The coil antennas 62D and 62E, which have the same winding directions,have operational effects similar to those of the coil antennas 20A and20B, and increase the energy transmission efficiency duringcommunication with the wireless IC tag 1A, thereby increasing thecommunication range. This also contributes to a reduction in the size ofthe communication terminal 60A. Note that when the coil antennas 62D and62E of the third modification example are used, two coil antennas neednot necessarily be used in the wireless IC tag.

Next, various modifications of the wireless IC tag will be described. Awireless IC tag 1B illustrated in FIG. 6 has a configuration in whichexternal electrodes 23A and 23B are located on a surface (bottomsurface) of the substrate 21 including the antennas 20A and 20B thereinso as to respectively face the antennas 20A and 20B. The rest of theconfiguration is preferably the same as that of the wireless IC tag 1A.Since the external electrodes 23A and 23B are provided, the wireless ICtag 1B can be soldered to an object such as a printed wiring substrate.

Referring to FIG. 7, meandering boost antennas 24A and 24B may beconnected to the external electrodes 23A and 23B of the wireless IC tag1B. Although, in this case, the boost antennas 24A and 24B preferablyare of the electric field radiation type, these may alternatively beboost antennas of the loop-shaped magnetic field radiation type.

A wireless IC tag 1C illustrated in FIG. 8A has a configuration in whichthe external electrodes 23A and 23B provided in the wireless IC tag 1Bare electrically connected to the coil antennas 20A and 20B. Referringto FIG. 8B, capacitors C1 and C2 may be inserted between the externalelectrodes 23A and 23B and the coil antennas 20A and 20B.

When the external electrodes 23A and 23B are directly electricallyconnected to the coil antennas 20A and 20B as illustrated in FIG. 8A,the relationship between the two potentials can be easily determined,whereby the impedances of the external electrodes 23A and 23B can beeasily set to various values. When the capacitors C1 and C2 are insertedas illustrated in FIG. 8B, since the external electrodes 23A and 23B arenot directly connected to the wireless IC chip 10, the wireless IC chip10 can be protected against intrusion of static electricity.

The antenna of a wireless IC tag may be, for example, a single-turnsingle-coil antenna 20C as illustrated in FIG. 9, or may be amultiple-turn single-coil antenna 20D as illustrated in FIG. 10, ratherthan a two-coil antenna. Further, it may be a coil antenna 25 located onthe front and back surfaces of a single film 24 as illustrated in FIG.11. In other words, the coil antenna 25 may be arranged such that a coilconductor 25 a wound in multiple turns is located on the front surfaceof the film 24, one end 25 a′ of the coil conductor 25 a is exposed onthe back surface of the film 24 and connected to a coil conductor 25 b,and the coil conductor 25 b is exposed on the front surface of the film24 and connected to a coil conductor 25 c.

Note that the antennas 20A and 20B of a wireless IC tag may havedifferent winding turns or different sizes, although not illustrated.Further, the number of coil antennas may be three or more. For example,another coil antenna may be inserted between the coil antennas 20A and20B.

Second Preferred Embodiment

Referring to FIGS. 12A and 12B, an information processing system 100Baccording to a second preferred embodiment has a configuration in whichan antenna 55 of a reader/writer 50 is of the small electric field typeand housed in a holder 56, and the antenna 55 is made to be insertableinto a casing 64 of a communication terminal 60B so as to be adjacent toan antenna portion 61. Referring to FIG. 12A, by mounting the antenna 55in the communication terminal 60B, reliable communication becomespossible in a state in which the antenna 55 and the antenna portion 61are close to each other. On the other hand, by taking out the antenna 55from the communication terminal 60B as illustrated in FIG. 60B,communication among elements spaced apart from one another is possibleas in the information processing system 100A.

Note that, by reducing the size of also the main body 51, thereader/writer 50 and the communication terminal 60B may be unified suchthat the main body 51 is housed in the holder 56 or pasted to the casing64.

Next, various modifications of the communication terminal will bedescribed. A communication terminal 60C illustrated in FIG. 13 is aterminal in which the dipole antenna portion 61 is arranged to extendfrom both sides of the coupling portion 62 in a meandering wing shape.The antenna portion 61 has a configuration in which a meanderingelectrode and a loop-shaped electrode which corresponds to the couplingportion 62 are formed on one surface of a resin film 65 using a thickfilm or thin film, and is placed in the tube-shaped casing 64 so as tobe folded upward at both sides of the coupling portion 62. The couplingportion 62 is arranged in the tip portion of the casing 64.

A communication terminal 60D illustrated in FIG. 14 has a couplingportion in which two planar electrodes 62 a and 62 b are formed, and therest of the configuration is similar to that of the communicationterminal 60C. The electrodes 62 a and 62 b function as an electric fieldantenna having a function similar to that of the antennas 62A and 62Billustrated in FIG. 3.

A communication terminal 60E illustrated in FIG. 15A has a configurationin which the antenna portion 61 having the coupling portion 62 has beenhoused in a casing 66 of a cellular phone. Referring to FIG. 15B, theantenna portion 61 has a configuration in which the electrodes 61 a and61 b and a loop-shaped electrode which corresponds to the couplingportion 62 are provided on one surface of a resin film 65 using a thickfilm or thin film, and is housed in the casing 66 so as to be bent by 90degrees at a portion connected to the coupling portion 62. The couplingportion 62 is arranged in a lower end corner of the casing 66.

A communication terminal 60F illustrated in FIG. 16 has a configurationin which an antenna portion 61 is constituted by an electric fieldmonopole antenna. The lower half of the antenna portion 61 includes acoaxial line covered by a tube-shaped ground electrode 68. One end ofthe loop-shaped coupling portion 62 is connected to the lower end of theantenna portion 61 and the other end is connected to the groundelectrode 68.

The monopole antenna, unlike the dipole antenna, preferably includes asingle conductor and, hence, the communication terminal 60F has aslender and simple structure, resulting in a reduction in manufacturingcost. Further, since the lower half is covered by the ground electrode68, a change in the antenna characteristics is small even when the lowerhalf is held by hand.

Other Preferred Embodiments

Note that a communication terminal and an information processing systemaccording to the present invention are not limited to the preferredembodiments described above, and various modifications are possiblewithin the scope of the present invention.

As described above, preferred embodiments of the present invention areuseful for a communication terminal and an information processing systemand, in particular, have an advantage in that the communication rangebetween a reader/writer and a wireless IC tag can be increased.

While preferred embodiments of the present invention have been describedabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the present invention. The scope of the present invention,therefore, is to be determined solely by the following claims.

What is claimed is:
 1. A communication terminal comprising: an antenna portion configured to be coupled with a reader/writer, the antenna portion including a coupling portion configured to be coupled with a wireless IC tag; and a hand-held casing; wherein the antenna portion and the coupling portion each is arranged to handle a signal used in a single information processing system; a signal for the single information processing system received by the antenna portion is transmitted from the coupling portion and a signal for the single information processing system received by the coupling portion is transmitted from the antenna portion without using a battery; and the antenna portion is located at one end portion of the casing; and the coupling portion is located at another end portion of the casing opposite to the one end portion of the casing, but is not located at the one end portion of the casing.
 2. The communication terminal according to claim 1, wherein the antenna portion is an electric field antenna.
 3. The communication terminal according to claim 2, wherein the electric field antenna is a dipole antenna.
 4. The communication terminal according to claim 3, wherein the coupling portion is arranged between two electrodes of the dipole antenna.
 5. The communication terminal according to claim 1, wherein the coupling portion includes a loop-shaped electrode.
 6. The communication terminal according to claim 1, wherein the coupling portion includes two planar electrodes.
 7. The communication terminal according to claim 1, wherein the antenna portion resonates at a frequency near an operation frequency of the reader/writer.
 8. The communication terminal according to claim 1, wherein the casing is tube-shaped.
 9. An information processing system comprising: a reader/writer; a communication terminal; and a wireless IC tag; wherein the communication terminal includes an antenna portion configured to be coupled with the reader/writer, the antenna portion including a coupling portion configured to be coupled with the wireless IC tag, and a hand-held casing; and the antenna portion communicates with the reader/writer; the coupling portion communicates with the wireless IC tag; and information stored in the wireless IC tag is read by the reader/writer; the antenna portion is located at one end portion of the casing; the coupling portion is located at another end portion of the casing opposite to the one end portion of the casing, but is not located at the one end portion of the casing; information stored in the wireless IC tag is read by bringing the coupling portion close to the wireless IC tag; and a signal for the information processing system received by the antenna portion is transmitted from the coupling portion to the wireless IC tag and a signal for the information processing system received by the coupling portion is transmitted from the antenna portion to the reader/writer without using a battery.
 10. The information processing system according to claim 9, wherein the antenna portion is an electric field antenna and the coupling portion includes a loop-shaped electrode.
 11. The information processing system according to claim 9, wherein a plurality of the communication terminals is provided.
 12. The information processing system according to claim 9, wherein an antenna of the reader/writer and the antenna portion are arranged in the casing so as to face each other.
 13. The information processing system according to claim 12, wherein the antenna of the reader/writer is removable from the casing.
 14. The information processing system according to claim 9, wherein the casing is tube-shaped. 